• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.365-370
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• 1997

Historical programs for genetic improvement of dairy cattle are discussed in the context of new genetic technologies resulting in a hetero zygous gain of function. Concepts are outlined pointing to the importance of breaking the well established genetic correlation between fat content and protein content of milk to provide flexibility in the dairy industry. The concept of value added genetics is introduced and the econ omic mpetitiveness of the mammary glands of livestock are considered in relationship to mammalian cell culture bacterial fermentation technology.

• KSBB Journal
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• v.16 no.1
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• pp.1-10
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• 2001

Escherichia coli has been used as an expression work horse for foreign genes. This article summarized recent development in genetic engineering techniques for overproduction of medical proteins and industrial enzymes. Special emphasis was placed upon research activities concerning folding and refolding of inclusion bodies at genetic and fermentation levels. Plasmid and mRNA stabilization, development of strong inducible promoters, modification of translational elements and reduction of rpoteolytic degradation were carried out to elevate an expression level of a target protein. Optimization of culture conditions, improvement of denaturation and renaturation steps and coexpression of molecular chaperones or foldase were accomplished to produce active proteins in soluble form. Fusion protein systems with selective separation and surface display technology were also performed in an effort to make the E. coli expression system more effective and versatile.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.157-160
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• 2003

ALA is an intermediate in the tetrapyrrole biosynthesis pathway and has extensive applications as a biodegradable herbicide and insecticide as well as medical applications including photodynamic therapy of cancers. For the development of mass production process of ALA it is necessary to on-line monitor some metabolites such as glycine, succinate, LA and ALA. In this study, medium compositions and fermentation conditions were investigated for enhancement of ALA production by recombinant E. coli. A 2-dimensional fluorescence sensor was employed to monitor the bioprocess of ALA production. The monitored data is analyzed using principal component analysis, a powerful tool for multivariate statistical analysis.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.514.3-515
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• 1986

λP$_{L}$ promoter와 Infiuenza virus의 NS1 Structural gene이 있는 pASl EH801 plasmid를 E. coli host N5' 과 AR120에 각각 transformation하여 온도와 nalidixic acid로 각각 induction 하여 보았다 N5151의 경우, O.D.600 1.2에서 42$^{\circ}C$로 induction하였을 때 maximum productivity를 보였으며 AR120의 경우는 O. D. 600 1.2, 37$^{\circ}C$, 40$\mu\textrm{g}$ nalidixic acid/$m\ell$ induction 하였을 때 maximum yield를 보여주었다. 이때 pH, DO, temperature, $O_2$%, $CO_2$%를 A/D converter통해 computer에 연결시켜 data acquision을 한 결과, 접종 후 ON-line induction이 가능함을 알 수 있었다.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.352-352
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• 2006

Corynebacterium glutamicum, which is well known as an amino acid fermentation bacterium, has been used as a producer of poly(3-hydroxybutyrate) [P(3HB)]. P(3HB) was synthesized in recombinant C. glutamicum harboring the expression plasmid vector with a strong promoter for cell surface protein gene derived from C. glutamicum and P(3HB) biosynthetic gene operon derived from Ralstonia eutropha. The expression of P(3HB) synthase gene was detected by enzyme activity assay. Intracellular P(3HB) was microscopically observed as inclusion granules and its content was calculated to be 22.5 % (w/w) with molecular weight of $2.1{\times}10^{5}$ and polydispersity of 1.63.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.619-622
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• 2000

For the production of $B^{30}-homoserine$ human insulin precursor, four types of fusion peptides LacZ, MBP, GST, and His-tagged sequence were studied in this work. Recombinant E. coli JM 103 and E. coli JM 109 containing fusion peptides were cultivated at $37^{\circ}C$ for 1hr, and gene expression was occurred when 0.5mM of isopropyl-D-thiogalactoside(IPTG) was added to the culture broth, and followed by longer than 4hr fermentation respectively. DEAE-Sphacel and gel filtration chromatography, amylose and glutathione-Sepharose 4B affinity chromatography, and nickel-affinity chromatography system were employed as purification of $B^{30}-homoserine$ human insulin precursor. Recovery yields of His-tagged, LacZ, GST, and MBP fused $B^{30}-homoserine$ human insulin precursor resulted in 47%, 20%, 20%, and 18%, respectively.

• KSBB Journal
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• v.6 no.1
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• pp.15-25
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• 1991

The optimal glucose concentration for the high-density culture of recombinant yeasts was obtained using dynamic simulation. An adaptive and predictive algoritilm complimented by the rule base was proposed for the control of the fed-batch fermentation process. The measurement of process variables has relatively long sampling period and relatively long time delay characteristics. As one of the solution on these problems, prediction techniques and rule bases were added to a classical recursive identification and control algorithm. Rule bases were used in the determination of control input considering the difference between the predicted value and the measured value. A mathelnatical model was used in the estimation and interpretation of the changes of state variables and parameters. Better performances were obtained by employing the control algorithm proposed in the present study compared to the conventional adaptive control method.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1448-1452
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• 2006

The effects of amplifying the gluconeogenic phosphoenolpyruvate carboxykinase of Escherichia coli ($pck_{Ec}$) on succinic acid production in E. coli were examined under anaerobic condition. No significant increase in succinic acid production was observed in E. coli overexpressing the $pck_{Ec}$ gene without supplementing $NaHCO_{3}$ or $MgCO_{3}$. On the other hand, succinic acid production was enhanced as the $NaHCO_{3}$ concentration was increased. When 20 g/l of $NaHCO_{3}$ was added, succinic acid production in recombinant E. coli overexpressing PCK was 2.2-fold higher than that observed in the wild-type strain. It was concluded that the gluconeogenic $pck_{Ec}$ overexpression enabled E. coli to enhance succinic acid production only under the high bicarbonate supplementation condition.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.153-159
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• 2009

Recombinant Escherichia coli BLR(DE3) harboring the hemA gene from Rhodobacter capsulatus under the control of a constitutive promoter, which we constructed previously, was used for the extracellular production of 5-aminolevulinic acid (ALA). The effects of several factors on ALA production were investigated in flask culture. ALA production by the recombinant E. coli was more efficient at $30^{\circ}C$ than $37^{\circ}C$. The glycine concentration had an important effect on cell growth. Glycine and succinic acid concentration of 5-10 and 10-20 g/L, respectively, resulted in high ALA production. In addition, the partial replacement of succinic acid by sodium glutamate increased the ALA production. The ALA production was inhibited by the presence of glucose in the medium. Using the optimal conditions, an ALA concentration of 8.2 g/L was achieved in jar fermentation without an added inducer or ALA dehydratase inhibitor; this is the highest reported concentration.

• KSBB Journal
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• v.20 no.2 s.91
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• pp.112-115
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• 2005

E. coli in combination with bacteriophage $\lambda$ was used to overcome the intrinsic plasmid instability that is frequently found in recombinant fermentation especially in long-term operation. In order to enhance the stability and productivity, the bacteriophage ${\lambda}NM1070$ was used in this study. It is a $\lambda$ mutant, which is deficient in the synthesis of protein related to DNA packaging and cell lysis. The ${\lambda}NM1070$ is also a temperature-sensitive mutant. To optimize the production of recombinant protein in this temperature-sensitive system, the temperature effects on growth and cloned gene expression were investigated for stable and efficient recombinant gene expression. The induction to the lytic state was not complete at $36^{\circ}C$ while the temperature above $40^{\circ}C$ induced the lytic state completely. However, the productivity was decreased at $42^{\circ}C$ by temperature inhibition. The L-free cell concentration increased with the increase of temperature until $40^{\circ}C$. In conclusion, ${\lambda}NM1070$ has the optimal temperature at $38^{\circ}C$ for stability and at $40^{\circ}C$ for expression.